1. Introduction to Corpus Linguistics: Dispersion/concordance plots
John Corbett and Wendy Anderson

2. This session Understanding concordance (or ‘dispersion’) plots
What are they and why are they useful?
Some case studies
Using free and commercial text analysis software
and
Developing our own questions

3. How does a topic pattern within texts?
Sometimes it is useful to know where in a text a word or group of related words occur.
Some text analysis programs (like freeware AntConc or the commercially-available WordSmith) allow you to show concordance/dispersion plots that indicate the position in the text where the word or words occur.

4. Download AntConc from www.laurenceanthony.net/software.html

5. Download text(s) to analyse, copy the text you want, clean it up and save it as a plain text file

6. Open your plain text file using AntConc
Open File View to check the file is ok
Click on Word List to generate frequencies
Click on Concordance to and search for your node (eg ‘independence’)

7. Then click on ‘Concordance Plot’ to find out where in the text the node occurs…

8. Summing up…concordance plots
Certain concordancing programs, like AntConc, will allow us to look at the way words are patterned or dispersed through a text. We can see quickly where there is ‘bunching’ ie where in a text a topic is covered and where it is neglected.
Comparing texts we can see similarity or difference in expression of particular concepts as the texts develop.

9. Developing your research tools…
So far, we have been considering a range of corpus analysis tools to analyse certain features of large bodies of texts.
We have been looking at
Frequency
Manual interpretation of concordances
Statistical measures of collocation (MI, t-score, z-score…)
Colligation
Concordance/dispersion plots
How would you develop and research your own question?

10. Some research questions (based on Davies 2010)
Lexical change and innovation:
How have words such as ‘globalisation’, ‘teenage’, ‘adolescent’, ‘same-sex’, ‘mentor’, ‘downsize’, etc entered the language. Have other words disappeared, eg ‘scullery’, or reappeared with a different sense ‘wireless’.
Morphological change and innovation:
How have suffixes like ‘-nik’, ‘-gate’ ‘-ista’ entered and diffused through the language? How about particular words like ‘flammable’ ‘inflammable’ ‘uninflammable’?

11. TIME magazine: frequency of ‘scullery’

12. TIME magazine: frequency of ‘wireless’

13. More research questions
Syntactical questions:
What are the most frequent phrasal verbs in British English/American English/different genres? How is the ‘get- passive’ used in English? How are constructions like ‘end up V-ing’ used in English?
Semantic questions:
Are the central and typical meanings of lexical items the same or different? Is ‘gather’ used more frequently to mean ‘collect’ or ‘understand’? How have the meanings of ‘gay’, ‘lame’, ‘green’, etc changed in the last decades?

14. Even more research questions
Discourse analysis:
What are we saying about issues like gender, the environment, politics, terrorism, revolution, immigration, etc that is different from what it was 10, 30 or 100 years ago?
In any given text about gender, the environment, politics, terrorism, etc, how are particular words or expressions (eg ‘woman’ or ‘battle’ or ‘I’) distributed?
Think of a question that particularly interests you. How would you begin to explore it? Which corpus tools would you select first?